Strong, machinable, heat-resistant alloy



Patented July 16, 1946 STRONG, MACHINABLE, HEAT-RESISTANT ALLOY Earl R. Parker, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York No Drawing. Application September 18, 1940,

Serial No. 357,283

4 Claims.

Th present invention relates to alloys and more particularly to a forgeable and freely machinable alloy which possesses high strength at elevated temperatures. Such an alloy is particu 2 may be precipitation hardenedby heating at a temperature of about 1000 to 1300 C. quenching and then reheating or drawing the alloy for one or more hours at a temperature of about 800 to larly desirable for use in the construction of 5 1000" C.

superchargers and gas turbines. These devices The presence of titanium permits the alloy to operate at temperatures in the neighborhood of be precipitation hardened and renders it strong 1200 to 1600 F. and under stresses up to about at high temperatures. The selenium makes the 20,000 pounds per square inch. alloy easily machinable While the manganese Heretofore four alloys have been employed'exmakes it more readily forgeable and also serves tensively in such devices. These alloys consist of: to deoxidize it. The manganese also Willcom- Per cent bine with any sulphur present in the alloy form- (1) Nickel 55 ing a high melting polnt sulphide.

M 1 M 1 20 The precipitation hardened alloy, at 1300 F., enum 2 has a 100 hour strength of 40,000 pounds per gi i square inch and a 1000 hour strength of 32,000 8 pounds per square inch and is therefore stronger P e t than the best prior art alloy. In addition how- 2) N k 1 as ever the alloy is freely machinable and easily Molybdenum 25 forgeable. As a result the present material is Manganese 2 extremely desirable material for use in the man- I Balance ufacture of devices such as superchargers, gas

I turbines, and the like, which operate under high Per cent stress and at elevated temperatures.

(3) Nlckel 20 The alloy ingredients hereinbefore pointed out,

Chrommm 13 are the only ones necessary to provide a forge- Tungsten 2 able, freely machinable alloy having high Molybdenum strength at elevated temperatures. If desired, Carbon tungsten may be substituted in whole or in part Balance for the molybdenum. However, such substitution cent generally will not be found to be desirable for (4) Chromium 1345 economic reasons. Cobalt may be substituted for Nickel a portion of the nickel although such substitution Iron Balance neither improves nor detracts from the properties of the alloy. A small quantity of chromium Y 2 IS the strongest of these four alloys- At may be present in the alloy and will increase the 1300 F. it has a 100 hour strength of 33,000 resistance of the alloy to oxidation. However,

Pounds pe Square inch and a 1000 hour St as the quantity of chromium is increased the alof 18,000 Pounds P Square inch- The 100 hour loy becomes increasingly difficult to forge and strength, for example, is the stress which will machine produce failure in hours. the I claim as new and desire to se ure by te p rature pr p s f the latter alloy are Letters Patent of the United States is:

tirely satisfactory it is almost impossible to ma- A forgeable readily machinable alloy com chine it. Alloy 1 may be machined although it taming about t 70% f nickel, 5 to 25% is extremely dimcult to d0 Alloys 3 and 4 are 46 of. metal from the group consisting of tungsten more readily machined, but are considerably and bd m, 0.5% to 5% titanium, 0.5% to Weaker t a 1 or 2 at high temperatures- 4% manganese, 0.1% to 0.5% selenium and the The alloy which constitutes the present invenbalance substantiauy all m tion is precipitation hardened and consists of 2 A forgeable readily machinable alloy about 50 to 70% nickel, 15 to 25% molybdenum, 50 tajnjng 50% t 70% nickel, 15% t 25% m01yb 0.5 to 5% tita ium, 0.5 to 4% manganese, 0.1 denum, 0.5% to 5% titanium, 0.5% to 4% manto 0.5% seleniu d t e b an iron- A p ganese, 0.1% to 0.5% selenium with the balance ferred composition consists of about nickel, substantially all iron.

20% molybdenum, 3% titanium, 2% manganese, 3. A forgeable, readily machinable alloy con- 0.25% selenium with the balance iron. The alloy 55 sisting of about 55 nickel, 20% molybdenum,

3% tit'anium 2% manganese, 0.25% selenium with the balance substantially all iron.

I 4. An alloy which is forgeable and freely machinable, said alloy being characterized by its high strength at temperatures in the neighborhood of 1200 to. 1600" F., said alloy containing a plurality of ingredients of which the following inthe proportions stated are the only ones necessary to attain said characteristics:

Iron

EARL R. PARKER. 

